I think people will take a look at this if you give them some time. I will do that myself. In the meantime I suggest switching to the VESA driver so that you have some sort of video if you haven't done so already. You won't get hardware acceleration or any other fancy features but X should run without crashing.

NetBSD still includes XFree86 in their file sets because XFree86 is well understood on all the platforms that NetBSD supports. Support for modular Xorg is improving, but it is not considered to be stable enough yet for all platforms.